A technique disclosed herein relates to drive units including a vibratory actuator and a support body configured to support the vibratory actuator, or drive units configured to drive a movable body, which is supported by a shaft, by using a vibratory actuator.
Drive units using a vibratory actuator are conventionally known in the art. For example, a drive unit described in Japanese Patent Publication No. 2006-067712 outputs a driving force by vibrating vibratory actuators formed by piezoelectric elements. Specifically, the drive unit of Japanese Patent Publication No. 2006-067712 includes two vibratory actuators provided with driver elements, and a shaft is held between the driver elements of the two vibratory actuators. By vibrating the vibratory actuators in this state, the driver elements are displaced according to the vibration of the vibratory actuators, whereby the shaft is driven in the axial direction thereof.
The tip end of the shaft is coupled with a lens frame of a lens unit. Specifically, a pin extending radially from the shaft is provided at the tip end of the shaft, whereas a long hole extending parallel to the shaft is provided in the lens frame. The pin at the tip end of the shaft is fitted in the long hole of the lens frame. The pin fitted in the long hole is pressed against one longitudinal end of the long hole by a plate spring, and is substantially fixed thereto, whereby displacement of the shaft in the axial direction thereof can be transmitted to the lens frame. Note that the width of the long hole is slightly greater than the outer diameter of the pin. That is, the pin is displaceable in the lateral direction of the long hole, and displacement of the pin in the lateral direction of the long hole is absorbed so as not to be transmitted to the lens frame.
Drive units configured to drive a movable body, which is supported by a shaft, by using a vibratory actuator are also conventionally known in the art. For example, a drive unit described in Japanese Patent Publication No. 2008-148425 includes a movable body formed as a rectangular frame, a shaft extending parallel to one side of the movable body and configured to support the movable body, and a vibratory actuator configured to drive the movable body along the shaft. The movable body has two through holes. Bearings are provided in these through holes, and the shaft is inserted through the bearings. The vibratory actuator has a vibrator provided inside the frame-shaped movable body. The vibrator is biased toward the movable body so as to contact the movable body. The vibrator is vibrated in this state to move the movable body along the shaft.